The average house price in London is £ 394.000 according to the land register. The average house square metre is 83. We take out on average 0.90 cubic metres for one chimney breast removed. £ 394.000 divided by 83 = £ 4,764.00 square metre of value onto the property. 4,764.00 times by 0.90 = £ 4,287.60 per chimney taken out. We add £17,148.00 for 4 chimney breasts on average. The cost is £4,200 make £12,948 profit for our clients.